A conversation among the three participants recorded in Lewis's rooms at Cambridge in December 1962.
(quote) Unreal Estates is the transcript of a recorded conversation between Lewis and the authors Brian Aldiss and Kingsley Amis that took place in Lewis' rooms in Magdalene College "a short while before illness forced him to retire".
--Wikipedia "Of Other Worlds" (2018-02-19) with internal quotation of the preface (HBJ 1966, p. 86)